Leukotriene and prostanoid pathway enzymes in bronchial biopsies of seasonal allergic asthmatics.

Cysteinyl-leukotrienes and prostaglandin D2 generated by the 5-lipoxygenase (5-LO) and cyclooxygenase (COX) pathways, respectively, cause bronchoconstriction, leukocyte recruitment, and bronchial hyperresponsiveness in asthma. We characterized the cellular expression of 5-LO and COX enzymes using immunohistochemistry on bronchial biopsies from 12 allergic asthmatic patients before and during seasonal exposure to birch pollen. Bronchial responsiveness (p = 0.004) and symptoms (p < 0.005) increased and peak expiratory flow (PEF; p < or = 0.02) decreased in the pollen season. In-season biopsies had 2-fold more cells immunostaining for 5-LO (p = 0.02), 5-LO-activating protein (FLAP; p = 0.04), and leukotriene (LT)A4 hydrolase (p = 0.05), and 4-fold more for the terminal enzyme for cysteinyl-leukotriene synthesis, LTC4 synthase (p = 0.02). Immunostaining for COX-1, COX-2, and PGD2 synthase was unchanged. Increased staining for LTC4 synthase was due to increased eosinophils (p = 0.035) and an increased proportion of eosinophils expressing the enzyme (p = 0.047). Macrophages also increased (p = 0.019), but mast cells and T-lymphocyte subsets were unchanged. Inverse correlations between PEF and 5-LO(+) cell counts link increased expression of 5-LO pathway enzymes in eosinophils and macrophages within the bronchial mucosa to deterioration of lung function during seasonal allergen exposure.

Identification in mice of two isoforms of the cysteinyl leukotriene 1 receptor that result from alternative splicing.

Two classes of human G protein-coupled receptors, cysteinyl leukotriene 1 (CysLT(1)) and CysLT(2) receptors, recently have been characterized and cloned. Because the CysLT(1) receptor blockers are effective in treating human bronchial asthma and the mouse is often used to model human diseases, we isolated the mouse CysLT(1) receptor from a mouse lung cDNA library and found two isoforms. A short isoform cDNA containing two exons encodes a polypeptide of 339 aa with 87.3% amino acid identity to the human CysLT(1) receptor. A long isoform has two additional exons and an in-frame upstream start codon resulting in a 13-aa extension at the N terminus. Northern blot analysis revealed that the mouse CysLT(1) receptor mRNA is expressed in lung and skin; and reverse transcription-PCR showed wide expression of the long isoform with the strongest presence in lung and skin. The gene for the mouse CysLT(1) receptor was mapped to band XD. Leukotriene (LT) D(4) induced intracellular calcium mobilization in Chinese hamster ovary cells stably expressing either isoform of the mouse CysLT(1) receptor cDNA. This agonist effect of LTD(4) was fully inhibited by the CysLT(1) receptor antagonist, MK-571. Microsomal membranes from each transformant showed a single class of binding sites for [(3)H]LTD(4); and the binding was blocked by unlabeled LTs, with the rank order of affinities being LTD(4) >> LTE(4) = LTC(4) >> LTB(4). Thus, the dominant mouse isoform with the N-terminal amino acid extension encoded by an additional exon has the same ligand response profile as the spliced form and the human receptor.

[Predonation of autologous blood for up to 6 weeks in MAP solution prior to elective cardiac surgery].

Predonation of autologous blood was performed by means of MAP solution prior to elective cardiac surgery. MAP solution made it possible to store in the fashion of fluid for 6 weeks. In twenty-three patients, total 39 times, predonation of autologous blood was performed prior to the elective cardiac surgeries. The mean volume of predonated blood was 583 ml (400-1200 ml)/case with MAP solution and 165 ml (0-400 ml)/case with conventional CPD solution, and the mean volume of total predonated blood was 748 ml (400-1600 ml)/case. The mean of the maximum duration of MAP predonate blood storage in individual cases was 25 days. Homologous blood transfusion was required in three cases. Two of the three cases had total aortic arch replacement under selective cerebral perfusion and the remainder was 76 year-old-man with unstable angina. In twenty cases (87%), any homologous blood transfusion was not performed throughout their clinical course. Twenty (95%) cases of 21 conventional cardiopulmonary bypass operation cases, except two selective cerebral perfusion cases, could successfully avoid homologous blood transfusion. To conclude, by using MAP solution, it became possible to take the longer period for predonation prior to elective surgery up to 6 weeks, compared with that in conventional way of storage by means of CPD solution. It seems worth-while to use MAP solution in order to take more predonated blood for avoiding homologous blood transfusion in elective cardiac surgery as far as possible.